Hi Marcol, sorry I've just posted you a thread but ddn't see your reply until after I sent it.
The reason I need the postcodes to be exactly correct is that we download files into the Royal Mail and Parcelforce interfaces to create the parcel labels. These 2 systems will only accept the postcodes in the exact format. At the moment we have to manually scrutinise and correct the csv files which is time consuming and inefficient.
Whilst writing this, I've just seen Stephen's post (#23) - all the postcodes are proper - I can't answer for the Post Office as to why they decided not to bring the London ones into line with the usual format; we just have to deal with them!